There is a strong trend in the aeronautical industry towards the More Electric Aircraft (MEA) concept as a consequence of substitutions of conventional equipments which depend on pneumatic, mechanic and hydraulic power by equipments that depend on electrical power which provide a better system performance due to increase of reliability, less maintenance, efficiency on energy conversion and therefore also higher efficiency of aircraft in general.
To cope with this increase of electrical power in the new distribution architectures, higher voltage levels are used for reducing the current levels and consequently the section of the wires and its weight. On the other hand, the major electrical loads can be powered directly from direct current instead of alternating three-phase current, which also means a decrease in the number of the wires that are used to connect the different electrical loads.
This considerable growth of the number of electrical loads in these new electric distribution architectures has contributed to an increase of the quantity of the electrical and electronic components, which could conduce to instability of the whole system due to the interactions between the different equipments that compose the system. Also, raising the level of voltage provokes the appearance of new problems regarding the function of some devices, such as conventional protections and other inconveniences originated by physical effects in the wires with the new levels of voltage: corona effect, arc fault and others.
In the aeronautical industry there is an increasing demand for Electrical Power Systems managed by smart control systems for, particularly, managing the connection and disconnection of the electrical loads depending on the operational mode and available power sources.
As a consequence, solid state power controllers (SSPCs) technology has been introduced inside the electrical management centers. These components have been grouped in Electrical Power Load Management Units (EPLMUs) which offer a number of advantages over electromechanical relays and conventional circuit breakers (CBs).
Other SSPC characteristics are high reliability, low power dissipation and remote control capability by means of complex hardware. Moreover, the devices based on power semiconductors, like the SSPCs, provide fast response and lower susceptibility to vibrations in comparison to electromagnetic and electro-mechanic components, such as CBs.
FIG. 3 shows a schematic view of a known EPLMU 17 based on SSPCs 33 with a Control Board 31 and input lines 22, 23, 26 for power supply and control (data communication).
The control of EPLMUs is usually done through a centralized Load Management Computer (LMC). The local control circuitry on each EPLMU is usually done via an internal data bus inside the Line Replacement Unit (LRU). Thus, SSPCs provides system intelligence, remote control and monitoring, less maintenance, less power dissipation, weight reduction and high reliability.
United State Patent Application US 2007/0081284 discloses a power control system based on SSPCs and conventional CBs. However, its design utilizes conventional CBs to provide power to some electrical loads, such as SSPC modules. Therefore, this architecture is limited to basic control and monitoring capability, and does not permit reduce volume and space.
Therefore it is desired to have an electrical secondary power system totally based on electronic components, such as SSPCs.
This invention is intended to the attention of this demand.